JavaScriptCore-7600.1.4.9.tar.gz

[apple/javascriptcore.git] / runtime / WeakMapData.cpp

diff --git a/runtime/WeakMapData.cpp b/runtime/WeakMapData.cpp
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+/*
+ * Copyright (C) 2013 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+ * THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+#include "WeakMapData.h"
+
+#include "CopiedAllocator.h"
+#include "CopyVisitorInlines.h"
+#include "ExceptionHelpers.h"
+#include "JSCJSValueInlines.h"
+#include "SlotVisitorInlines.h"
+
+#include <wtf/MathExtras.h>
+
+namespace JSC {
+
+const ClassInfo WeakMapData::s_info = { "WeakMapData", 0, 0, 0, CREATE_METHOD_TABLE(WeakMapData) };
+
+WeakMapData::WeakMapData(VM& vm)
+    : Base(vm, vm.weakMapDataStructure.get())
+    , m_deadKeyCleaner(this)
+{
+}
+
+void WeakMapData::finishCreation(VM& vm)
+{
+    Base::finishCreation(vm);
+}
+
+void WeakMapData::destroy(JSCell* cell)
+{
+    static_cast<WeakMapData*>(cell)->~WeakMapData();
+}
+
+void WeakMapData::visitChildren(JSCell* cell, SlotVisitor& visitor)
+{
+    Base::visitChildren(cell, visitor);
+    WeakMapData* thisObj = jsCast<WeakMapData*>(cell);
+    visitor.addUnconditionalFinalizer(&thisObj->m_deadKeyCleaner);
+    visitor.addWeakReferenceHarvester(&thisObj->m_deadKeyCleaner);
+
+    // Rough approximation of the external storage needed for the hashtable.
+    // This isn't exact, but it is close enough, and proportional to the actual
+    // external mermory usage.
+    visitor.reportExtraMemoryUsage(thisObj, thisObj->m_map.capacity() * (sizeof(JSObject*) + sizeof(WriteBarrier<Unknown>)));
+}
+
+void WeakMapData::set(VM& vm, JSObject* key, JSValue value)
+{
+    // Here we force the write barrier on the key.
+    auto result = m_map.add(WriteBarrier<JSObject>(vm, this, key).get(), WriteBarrier<Unknown>());
+    result.iterator->value.set(vm, this, value);
+}
+
+JSValue WeakMapData::get(JSObject* key)
+{
+    auto iter = m_map.find(key);
+    if (iter == m_map.end())
+        return jsUndefined();
+    return iter->value.get();
+}
+
+bool WeakMapData::remove(JSObject* key)
+{
+    auto iter = m_map.find(key);
+    if (iter == m_map.end())
+        return false;
+
+    m_map.remove(iter);
+    return true;
+}
+
+bool WeakMapData::contains(JSObject* key)
+{
+    return m_map.contains(key);
+}
+
+void WeakMapData::clear()
+{
+    m_map.clear();
+}
+
+void WeakMapData::DeadKeyCleaner::visitWeakReferences(SlotVisitor& visitor)
+{
+    m_liveKeyCount = 0;
+    for (auto it = m_target->m_map.begin(), end = m_target->m_map.end(); it != end; ++it) {
+        if (!Heap::isMarked(it->key))
+            continue;
+        m_liveKeyCount++;
+        visitor.append(&it->value);
+    }
+    RELEASE_ASSERT(m_liveKeyCount <= m_target->m_map.size());
+}
+
+void WeakMapData::DeadKeyCleaner::finalizeUnconditionally()
+{
+    if (m_liveKeyCount > m_target->m_map.size() / 2) {
+        RELEASE_ASSERT(m_liveKeyCount <= m_target->m_map.size());
+        int deadCount = m_target->m_map.size() - m_liveKeyCount;
+        if (!deadCount)
+            return;
+        Vector<JSObject*> deadEntries;
+        deadEntries.reserveCapacity(deadCount);
+        for (auto it = m_target->m_map.begin(), end = m_target->m_map.end(); it != end; ++it) {
+            if (Heap::isMarked(it->key))
+                continue;
+            deadEntries.uncheckedAppend(it->key);
+        }
+        for (size_t i = 0; i < deadEntries.size(); i++)
+            m_target->m_map.remove(deadEntries[i]);
+    } else {
+        MapType newMap;
+        for (auto it = m_target->m_map.begin(), end = m_target->m_map.end(); it != end; ++it) {
+            if (!Heap::isMarked(it->key))
+                continue;
+            newMap.add(it->key, it->value);
+        }
+        m_target->m_map.swap(newMap);
+    }
+}
+
+}